Leaders of Pakistan’s rival political parties and top military commanders have begun an “all-party conference” in Islamabad to try to formulate a national response to U.S. allegations that the country is not doing enough to eliminate terrorist sanctuaries on its soil, and that Pakistan's spy agency is supporting insurgents in neighboring Afghanistan.

Relations between Pakistan and the U.S. have plunged to new lows since last Thursday, when outgoing U.S. Chairman of the Joint Chiefs of Staff Adm. Mike Mullen accused the Pakistani spy agency, ISI, of supporting and aiding militants linked to the Haqqani network in attacking U.S. forces in Afghanistan. Mullen called the Haqqani network a "veritable arm" of the ISI.

The allegations - rejected by Islamabad as baseless - have triggered fears the U.S. may launch direct military strikes against the Haqqani bases in Pakistan’s North Waziristan region on the Afghan border.

On Thursday, Prime Minister Yousuf Raza Gilani gathered leaders of the country's political parties, as well as its military commanders, in Islamabad to discuss Adm. Mullen's allegations.

In his opening remarks to the multi-party conference, Gilani said that the U.S. must stop blaming his country for regional instability. He said the blame game is counter-productive and should end, adding that Pakistan’s red lines and national interests must be respected. Gilani said any differences over perceptions or issues would be best resolved through a constructive dialogue to which Pakistan’s doors are open.

The prime minister said his country cannot be pressured into doing more, again dismissing criticism of Pakistan’s anti-terror efforts as misplaced. He said the country has made more sacrifices than any other nation in the war against the militants, losing thousands of security personnel.

Pakistani officials say that Lt. General Ahmed Shuja Pasha, head of the ISI, will respond to questions raised by politicians about whether there is any truth to the U.S. allegations.

Haqqani offensive considered

Military authorities are also expected to discuss whether an offensive against militants hiding in the North Waziristan territory can be undertaken at this stage. The country’s foreign minister, Hina Rabbani Khar, has also briefed the participants of the conference on details of her talks with American leaders during her recently concluded trip to New York.

The U.S. has long wanted Pakistan to move forces against bases of the Haqqani network in the Waziristan region to prevent militants from attacking U.S. and NATO forces in Afghanistan.

Demands have grown in the U.S. Congress in recent days for expanding American military action in Pakistan beyond the drone strikes that are already targeting militants of the al-Qaida-linked Haqqani network.

The former head of the political science department at the University of the Punjab, Professor Hassan Askari Rizvi, said Thursday's conference would not lead to any significant changes in Pakistan's foreign policy.

"[An] All-Party Conference ... emphasizes certain things [and] gives some kind of advice, some kind of ideas, which are taken into account while foreign policy is being formulated," he said. "So you should not expect that there would be some radical change in foreign policy. I think there will be a kind of expression of solidarity in view of the American pressure."

Rizvi believes Pakistan does not want a further deterioration of U.S. ties. U.S. leaders also seem to have toned down their criticism, and he said the two countries realize that they need each other for a smooth security transition in Afghanistan and the withdrawal of all foreign combat forces from the country by 2014.

Pakistan has also stepped up its diplomatic contacts with neighboring countries - particularly with its longstanding ally, China, and with Iran. Top security officials from both countries visited Islamabad this week to reiterate their support for Pakistan.

Counter accusations against Washington

Top Pakistani leaders, while denying accusations that their country has sponsored militant attacks on U.S. interests in Afghanistan, have in turn accused Washington of making Pakistan a scapegoat for U.S. failures in the Afghan conflict.

Thursday’s meeting of Pakistani politicians and military leaders comes a day after Secretary of State Hillary Clinton said the U.S. is conducting a final review on whether to designate the Haqqani network a terrorist organization.

White House spokesman Jay Carney said on Wednesday that he would not have used the same language as Adm. Mullen, but that the U.S. wants Islamabad to take action against Haqqani safe havens in Pakistan.